Currently, most glasses that are produced have lenses with fixed focal lengths, which is problematic for individuals whose eyesight may be changing and/or for those wishing to view things at different distances. Even if some of these glasses can be repositioned to change focus (e.g. based on which portion of a bifocal lens is being looked through), such manipulation is to be done manually by a user. This can be cumbersome, inadequate, and imprecise, to say the least.